Erythrocyte Carbonic Anhydrase Isoenzymes Research Articles

β-D-Glukan, Lektin, Linoleik Asit ve β-Karoten Bileşiklerinin Karbonik Anhidraz Enzimleri Üzerindeki Etkilerinin Araştırılması

β-D-glukan, lektin, linoleik asit ve β-karoten; hayvansal, bitkisel ve bakteriyel kaynaklarda bulunan, biyolojik olarak aktif bileşiklerdir. Glokom, dünya genelinde körlüğe neden olma bakımından katarakttan sonra ikinci sırada gelen bir hastalıktır. Karbonik anhidraz (CA) inhibitörleri uzun yıllardır glokom tedavisinde kullanılmaktadır. Ancak, inhibitör ajanların yan etkileri azımsanmayacak derecede çoktur. Yeni CA inhibitörlerinin geliştirilmesi üzerine çeşitli araştırma grupları çalışmalar yapmaktadırlar. Doğal kaynaklı bileşiklerin CA inhibitörü olarak kullanımının araştırılması da son yıllarda popülerlik kazanmıştır. Bu çalışmada, β-D-glukan, lektin, linoleik asit ve β-karoten bileşiklerinin, insan eritrosit CA izoenzimleri olan hCA I ve hCA II üzerine etkileri in vitro koşullarda araştırılmıştır. Bileşiklerin Ki değerleri hCA I için 0.45±0.09 µM − 37.02±17.85 µM aralığında, hCA II için 3.12±1.38 µM − 61.23±25.46 µM aralığındadır.

Evaluation of Inhibition Effects of Some Cardiovascular Therapeutics on Human Erythrocyte Carbonic Anhydrase Isoenzymes

Abstract Carbonic anhydrase enzyme plays a vital role in metabolic events such as acid-base regulation and respiration. In our research, it is tried to determine the inhibitory influences of the cardiovascular therapeutics esmolol hydrochloride, amiodarone hydrochloride and lidocaine hydrochloride on human erythrocytes carbonic anhydrases (hCAI and II). In accordance with this purpose, carbonic anhydrase isoenzymes were purified from human erythrocytes by using affinity chromatography method. Enzyme purity was checked by SDS-PAGE electrophoresis method. After the aldose reductase enzymes were purified, the inhibitory affects of cardiovascular therapeutics on these enzymes, using esterase activity, which is the method of measuring in vitro activity, were examined. The three cardiovascular therapeutics dose-dependently decreased activity of hCAs. IC 50 values of amiodarone hydrochloride, esmolol hydrochloride and lidocaine hydrochloride were found to be, respectively, 0.91 mM, 5 mM, 5.8 mM for hCA-I and 0.41 mM, 3.5 mM, and 6.36 mM for hCA-II. Our results proved that, under in vitro conditions, cardiovascular therapeutics significantly inhibit human CA-I and II activities. So, irregular use of these medicines may cause serious adverse effects in terms of human health.

The effect of ethanol on erythrocyte carbonic anhydrase isoenzymes activity: An in vitro and in vivo study

The ethanol is a widely consumed as sedative-hypnotic drug throughout the world. In this study, the effects of ethanol were investigated on carbonic anhydrase (CA) enzyme activities both in vitro in human erythrocyte and in vivo in Sprague-Dawley rat erythrocyte. For in vitro study, the human carbonic anhydrase-I (HCA-I) and -II (HCA-II) are purified by Sepharose 4B–L-tyrosine-sulphanilamide affinity chromatography. In vivo CA enzyme activity was determined colorimetrically by using CO2-hydration method of Wilbur and Anderson. Rat blood samples were taken from each rat before and after the ethanol administration at different times (1 h, 3 h, and 5 h). Rat erythrocyte CA activity was significantly inhibited by pharmacological dosage of the ethanol (2 mL.kg− 1) for up to 3 h (p < 0.001) following intraperitoneally administration. The ethanol showed in vitro inhibitory effects on HCA-I and HCA-II hydratase activity, determined by colorimetrically using the CO2-hydratase method. The inhibitor concentrations causing up to 50% inhibition (IC50) were 2.09 M for HCA-I (r2:0.9273) and 1.83 M for HCA-II (r2:9749). In conclusion, it was demonstrated that carbonic anhydrase enzyme in erythrocytes was significantly inhibited by the ethanol both in in vitro and in vivo.

Carbonic anhydrase isoenzyme B in erythrocytes of subjects with chronic acidosis

A specific and quantitative immunological method for determination of human erythrocyte carbonic anhydrase isoenzyme B has been used to ascertain the contents of this enzyme in the erythrocytes of healthy persons and of subjects with chronic metabolic and respiratory acidosis. The investigations have shown significant increase of carbonic anhydrase type B in the erythrocytes of patients suffering from renal failure with chronic acidosis, and in patients with chronic obstructive lung disease and chronic respiratory acidosis. The erythrocytes of acidotic uremie patients have a significantly higher content of erythrocyte carbonic anhydrase isoenzyme B than do the erythrocytes of uremie subjects without chronic acidosis. In chronic obstructive lung disease, the content of this enzyme in erythrocytes was significantly higher in the hypercapnic patients than in the normocapnic ones. In renal failure, significant correlation was found between carbonic anhydrase isoenzyme B and standrad bicarbonate. In chronic obstructive lung disease no significant correlation was found between carbonic anhydrase and pCO 2.

Carbonic anhydrase isoenzyme B in erythrocytes of anemic and non-anemic uremic subjects

A specific and quantitative immunological method for determination of human erythrocyte carbonic anhydrase isoenzyme B has been used to determine the contents of this enzyme in the erythrocytes from healthy persons and anemic and non-anemic subjects with renal insufficiency. The investigations have shown significant increase of carbonic anhydrase type B in the erythrocytes of patients with renal failure. The erythrocytes of anemic uremie patients have a significantly higher content of erythrocyte carbonic anhydrase isoenzyme B than the erythrocytes of non-anemic uremic subjects. Significant correlations were found between human erythrocyte carbonic anhydrase type B and hemoglobin and between it and plasma bicarbonate. No correlation was found between human erythrocyte carbonic anhydrase and plasma creatinine or creatinine clearance and serum zinc.

Carbonic anhydrase isoenzymes in the erythrocytes of new-born premature and full-term infants

A specific and quantitative immunological method for the determination of human erythrocyte carbonic anhydrase isoenzymes B and C has been used to determine these enzymes in erythrocytes of umbilical cord blood. The investigations have shown a content of both isoenzymes less than 1 : 10 of that in adults. Premature infants have significantly lower values than full-term infants. The influence of carbonic anhydrase in the respiratory distress syndrome is discussed. No conclusions are drawn. The content of carbonic anhydrase in erythrocytes has been suggested as a laboratory parameter of maturity. In our investigations it does not seem to be useful for the evaluation of maturity.

Thermal inactivation studies of normal and variant human erythrocyte carbonic anhydrases by using a sulphonamide-binding assay

Heat-inactivation studies were carried out on the two primary erythrocyte carbonic anhydrase isoenzymes, CA I and CA II, and the secondary isoenzyme of CA I, CA I (+1). In addition, two genetic variants of human isoenzyme CA I, CA Id Michigan (100 Thr-->Lys) and CA If London (102 Glu-->Lys), and one variant of isoenzyme CA II, CA IIh (251 Asn-->Asp), were similarly analysed. The first-order rate constants and Arrhenius plots for these six enzyme forms showed that (1) isoenzyme CA II is more heat-stable than CA I, (2) isoenzyme CA I (+1) is less heat-stable than CA I, (3) the variants CA IIh and CA If London are less heat-stable than the normal enzymes, and (4) isoenzyme CA Id Michigan is more heat-stable than normal CA I. From the values of the slopes of the Arrhenius plots, the energy of activation (E(a)) for each isoenzyme and isoenzyme variant was determined, and the following thermodynamic activation parameters were calculated at 55 degrees C: the free energy of activation (DeltaG(double dagger)), the activation enthalpy (DeltaH(double dagger)) and the activation entropy (DeltaS(double dagger)). The DeltaG(double dagger) for the enzymes shows a relative constancy with compensating variation in DeltaH(double dagger) and DeltaS(double dagger). When the values for DeltaH(double dagger) are plotted against DeltaS(double dagger), an increase in DeltaH(double dagger) involves a concomitant increase in DeltaS(double dagger).

Red-cell carbonic anhydrase isoenyzmes in megaloblastic anaemia.

Erythrocyte carbonic anhydrase isoenzymes B and C have been measured by means of electrophoresis on cellulose acetate membrane strips followed by staining, elution and spectrophotometry. The results from 30 normal subjects showed for carbonic anhydrase B a mean and standard deviation of 12.1 ± 1.4 mg/g Hb, and for carbonic anhydrase C, 3.9 ± 0.9 mg/g Hb.Both isoenzymes were markedly increased in all 10 cases of untreated megaloblastic anaemia, the mean ± SD for carbonic anhydrase B being 24.8 ± 7.6 mglg Hb and for the isoenzyme C, 7.7±k 1.2 mg/g Hb. These results are both highly significantly greater than the normal means (P &lt; 0.001). The elevated levels of both isoenzymes returned to the normal range within 2–4 weeks of starting vitamin B12 therapy in 3 patients with pernicious anaemia in whom serial enzyme measurements were made. In a group of 13 patients with pernicious anaemia, who had been adequately treated with vitamin BIZ for 1–15 years, the mean levels of isoenzymes B and C were 10.3 ± 0.6 and 2.9 ± 0.7 mg/g Hb respectively; both these mean results are significantly less than the corresponding normal means (P &lt; 0.001).

Carbonic anhydrase isoenzyme B in the erythrocytes of uremic subjects

A specific and quantitative immunological method for determination of human erythrocyte carbonic anhydrase isoenzyme B has been used to determine the contents of enzyme in the erythrocytes from healthy persons and subjects with uremia. The investigations have shown a significant increase of carbonic anhydrase type B in the erythrocytes of patients with renal failure. Correlation was found between human erythrocyte carbonic anhydrase type B and Pt-creatinine-clearance but not between it and plasma standardbicarbonate.

Electrophoretic distribution of human erythrocyte carbonic anhydrase isoenzymes and of carbonic anhydrase-like activity in human blood serum

Electrophoretic distribution of human erythrocyte carbonic anhydrase isoenzymes and of carbonic anhydrase-like activity in human blood serum